Receding Front Method: A New Approach Applied to Generate Hexahedral Meshes of Outer Domains

Two of the most successful methods to generate unstructured hexahedral meshes are the grid-based methods and the advancing front methods. On the one hand, the grid-based methods generate high quality elements in the inner part of the domain using an inside-outside approach. On the other hand, advancing front methods generate high quality hexahedra near the boundary using an outside-inside approach. In this paper we propose the receding front method, an original approach that combines the advantages of both methodologies: we use an inside-outside mesh generation approach by means of a reversed front advance. We apply this approach to mesh outer domains. To reproduce the shape of the boundaries, we first precompute the mesh fronts by combining two solutions of the Eikonal equation on a tetrahedral reference mesh. Then, to generate high quality elements, we expand the quadrilateral surface mesh of the inner body towards the unmeshed external boundary using the pre-computed fronts as a guide. Further research is under way in order to apply the proposed method to more complicated geometries.